Research on dual-terminal synchronization and ranging for laser communication link

Abstract

With the development of technologies such as spatial information networks, precision time synchronization and distance measurement have played a paramount role in space laser links. Time synchronization is the basis of bidirectional laser ranging, and its accuracy significantly affects the quality of laser communication and ranging. However, the only way for the current integrated communication and ranging system to improve the system’s time synchronization accuracy is to increase the communication rate. It is impossible to achieve higher-precision time synchronization. In this study, we propose a coarse and fine composite time synchronization algorithm for laser communication link. Based on a high-precision time synchronization protocol, a small amount of ranging timestamps are added to the communication data frame for dual terminals time exchange as a coarse measurement ruler. And use the precise mixing phase comparison of the communication data recovery clock as a fine measuring ruler. The exact phase difference between the dual-terminal of the laser link is obtained, and the experimental work of the synchronization algorithm is performed in an equivalent space link. The experiment shows that the double-ended time synchronization accuracy is 90ps(3σ), which can be well applied to laser communication and ranging links.